public JsonResult SavedEvent(string eventTitle, string startTime, string endTime, bool isAllDay, bool isFixed)
        {
            try
            {
                if (Session["student"] == null)
                {
                    return Json(false);
                }

                EventModel eventModel = new EventModel
                {
                    EndTime = DateTime.Parse(endTime),
                    StartTime = DateTime.Parse(startTime),
                    EventTitle = eventTitle,
                    IsAllDay = isAllDay,
                    IsFixed = isFixed,
                    Color = isFixed ? "green" : "red"
                };
                Guid id = Guid.Parse((string)Session["student"]);
                using (var context = new TobyDBContext())
                {
                    eventModel.StudentId = id;
                    context.EventModels.Add(eventModel);
                    context.SaveChanges();
                }
                return Json(eventModel.Id);
            }
            catch { return Json(false); }
        }
        public JsonResult SavedEvents(EventJsonModel jsonModel)
        {
            DateTime start, end, temp;
            EventModel eventModel;

            try
            {
                if (jsonModel.studentIds == null)
                {
                    throw new Exception();
                }

                if (DateTime.TryParse(jsonModel.startTime, out start) && DateTime.TryParse(jsonModel.endTime, out end))
                {
                    if (start > end)
                    {
                        temp = start;
                        start = end;
                        end = temp;
                    }
                }
                else
                {
                    throw new Exception();
                }

                using (var context = new TobyDBContext())
                {
                    jsonModel.studentIds.ForEach(id =>
                        {
                            eventModel = new EventModel
                            {
                                EventTitle = jsonModel.eventTile,
                                StartTime = start,
                                EndTime = end,
                                StudentId = id,
                                TeacherId = jsonModel.teacherId,
                                WorkTypeId = jsonModel.workTypeId,
                                Color = "red",
                                IsFixed = false,
                                IsAllDay = false
                            };
                            context.EventModels.Add(eventModel);
                        });

                    context.SaveChanges();
                }

                return Json(true);
            }
            catch
            {
                return Json(false);
            }
        }